This research is based on the development of new methodology specifically degigned to determine the localization of radioactively labeled narcotic agonists and narcotic antagonists in tissue at the cellular level. The method is based on the use of freeze dried frozen sections from which both autoradiographic and fluorescence data may be derived from selfsame areas of tissue by visual scanning and photomicrography while the tissue section is held in a locked position on the microscope stage. By this method it is possible to determine what correlation,if any, exists between the localization of the drug and the biogenic amine content of cells. With the methodology now available we will first study the localization of H3 labeled morphine in mouse brain using the autoradiographic technique designed for use with diffusible compounds. When this survey is completed we will re-examine the labeled areas to determine the coincidence of autoradiographic labeling of cells with their biogenic amine content as measured by microspectrofluorescence. After the basic distribution and correlation data on morphine and biogenic amines have been obtained the program of research will be extended to study other narcotic analgesic agonist and antagonists. The addition of immunofluorescent antibody techinques combining autoradiography, endogenous fluorescence and immunofluorescence in a cytopharmacological study of three or more factors is now potentially available.